Cable for power-over-ethernet having an extended usable length

ABSTRACT

A method of extending the usable length of a power-over-ethernet cable includes the steps of providing twisted pairs of wires with the conductor of each wire being a 20 AWG or 22 AWG conductor and terminating the cable at an RJ-45 style connector. The connector for the 20 AWG conductors has an insert therein with holes that can accommodate 20 AWG conductors. FEP, PVC or PP insulation may surround each conductor.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/080,936, filed Mar. 25, 2016, which claims the benefit of U.S.Application Ser. No. 62/138,575, filed Mar. 26, 2015, the disclosures ofwhich are incorporated herein by reference in their entirety.

FIELD OF THE DISCLOSURE

The present disclosure is directed to electrical cable and moreparticularly to cable which simultaneously transmits power and datasignals.

BACKGROUND

Power-Over-Ethernet (POE) is about twenty years old and has beenmainstream for about six or seven years. Among other things, it is usedto power security cameras. It replaces coaxial cable for this purpose.You could also use fiber optic cable for this purpose but the use offiber optic cable brings numerous complexities and attendant problems.

In POE cable electrical power is transmitted over the same twisted pairwires as the data signals. Typical POE cable is Category 5e or Category6 (also known as Cat 5e or Cat 6) twisted pair cable. Cat 5e and Cat 6are open specifications set by the Telecommunications IndustryAssociation (TIA), an offshoot of the Electronic Industries Alliance(EIA). Cat 5e cable is always 24 gauge AWG (American wire gauge). Cat 6is 23 or 24 gauge AWG.

Presently the maximum length of a POE cable having these specificationsis 100 meters. Once you go beyond that length you have to add a boosteror an intermediate distribution frame (IDF) that is powered off thegrid. Users would like to extend that 100 meter distance without havingto incorporate boosters or IDF's, which just add complexity and cost.The TIA publishes a document TSB-184A D4 for Guidelines for SupportingPower Over Balanced Twisted-Pair Cabling. It is noted that this documentonly is applicable to mid-span power, which requires that a POE injectorwith a power supply be installed in a tamper-proof cabinet every 328feet. This increases the cost of the installation and also addspotential points of failure to a video surveillance system. Theend-to-end POE power supply approach of the present disclosure onlyrequires that power be supplied on one end of the system.

SUMMARY

In one aspect, the present disclosure concerns a twisted pair cable witha particular gauge, insulation type and connector that permits extendingthe usable length of power-over-ethernet cable. The cable of theinvention has a similar lay of twist as Cat 5e or Cat 6 cable. The twistis necessary to avoid cross-talk. The invention uses 20 AWG solid copperconductors in four twisted pairs. In one embodiment each conductor hasFEP (fluorinated ethylene propylene) insulation and an overall FEPjacket. The insulation thickness is 0.012 inches. The connector is anRJ-45 style connector having an insert with holes that can accommodatethe conductor and insulation of 20 AWG wires. This cable hassuccessfully performed with video cameras, and no IDF's or boosters, atlengths of at least 292 meters with full resolution 1080p video at 30fps using the RJ-45 connectors described herein. This is almost threetimes the distance standard category 5 or 6 cables can traverse withoutboosters or IDF's.

An alternate embodiment utilizes 22 AWG conductors with conventionalRJ-45 connectors. The reach of this system is more than twice that ofthe mid-span approach.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of the cable with an endof the jacket removed to show the four twisted pairs of wires and aripcord.

FIG. 2 is a cross-section of the cable of FIG. 1.

FIG. 3 is a side elevation view of a connector used with the cable ofthe present disclosure.

FIG. 4 is an end elevation view of the rear end of the connector of FIG.3, with the shield removed to show only the housing.

FIG. 5 is a top plan view of the connector of FIG. 3.

FIG. 6 is an end elevation view of the front end of the connector ofFIG. 3.

FIG. 7 is a bottom plan view of the connector of FIG. 3.

FIG. 8 is a side elevation view of a contact blade, on an enlargedscale.

FIG. 9 is a perspective view of the insert block used in the connectorof FIG. 3.

FIG. 10 is a top plan view of the insert block of FIG. 9.

FIG. 11 is an end elevation view of the insert block.

FIG. 12 is a side elevation view of the insert block.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure is directed to a cable for power-over-ethernet(POE) applications. The disclosure particularly concerns a method ofextending the usable length of POE cables. An end portion of oneembodiment of the cable is shown generally at 10 in FIG. 1. Thisembodiment is identified in the table below as UTP 20AWG Cat6 CMP orCL3P. The cable includes an outer jacket 12 which in this embodiment ismade of fluorinated ethylene propylene (FEP). The jacket has a wallthickness of about 0.013″ and a diameter of about 0.248″. The color mayvary but an example is translucent blue. Preferably a ripcord 14 isincluded, although it is not required. A jacket this size has a weightof about 53 lbs/Mft.

The jacket 12 surrounds four twisted pairs of wires as seen at 18, 20,22, 24. Each pair has two individual wires as shown by the designationsA and B. Color codes may vary but, for example, pair 18 could begreen×white/green, pair 20 could be brown×white/brown, pair 22 could beblue×white/blue, and pair 24 could be orange×white/orange. The pair laylength could be 1.40″ LHL (8.57 Tw/Ft) (each pair staggered lay length).The cable lay length could be 5.00″ LHL (2.40 Tw/Ft).

FIG. 2 shows a cross section of the cable of FIG. 1. In FIG. 2 thetwisted pairs 18-24 are indicated diagrammatically by the circles. Eachwire has a central conductor (one of which is shown at 32) which is 20AWG solid annealed bare copper. The insulation (one of which is shown at34) surrounding the conductor in this embodiment is fluorinated ethylenepropylene (FEP) having a wall thickness of 0.012″.

The electrical characteristics of the cable include an impedance of98.80Ω/Mft±10%, a capacitance of 15.0 pF/ft±10% and a DC resistance of10.3Ω/Mft @ 20° C. The cable is UL listed as type CL3P per UL standard13 and as type CMP c(UL)us 200° C. FT-6 per UL standard 444. Allmaterials used in the manufacture of this cable are RoHS II & REACHCompliant. The maximum operating voltage is 300V.

The cable as described delivers a greater distance while still beingable to use connectors whose exterior dimensions are the same asstandard RJ-45 connectors but whose interior is adapted to accept 20 AWGconductors.

In alternate embodiments polypropylene or PVC insulation could be usedthat will provide similar results. This will enable cables which areappropriate for all types of installations at a cost commensurate withthe physical demands on the cables. That is, the first embodiment as inFIGS. 1 and 2 with FEP insulation is for plenum-rated cable which can beinstalled in air ducts and plenum spaces. An alternate embodiment willbe cable which will not be plenum-rated but may still be run exposed inany other case and which may penetrate floors in a multi-level dwellingor commercial environment. The low-smoke, zero-halogen product is aimedat customers with a concern regarding the use of PVC and/or in enclosedspaces where the use of halogens as flame retardants could be hazardous.FEP which is used in the plenum-rated product is the highest costcompound that results in the most expensive cable. The other twoembodiments will have lower costs as the compounds are about 1/7^(th) to1/10^(th) the cost of FEP. The following table shows exemplaryembodiments which have been found to be successful, although it will beunderstood that additional embodiments are possible.

UTP 20AWG All dimensions in UTP 20AWG UTP 20AWG UTP 20AWG Cat6 CMP ormillimeters Cat5E CMP Cat5E CM-LSZH Cat5E CMR CL3P Conductor MaterialSolid annealed Solid annealed Solid annealed Solid annealed bare copperwire bare copper wire bare copper wire bare copper wire Composing1/0.813 1/0.813 1/0.813 1/0.813 Diameter 0.813 ± 0.01  0.813 ± 0.01 0.813 ± 0.01  0.813 ± 0.01 Insulation Material FEP HDPE HDPE FEP Wallthickness, nom 0.2935 0.2935 0.2935 0.3048 Diameter 1.40 ± 0.05 1.40 ±0.05 1.40 ± 0.05 Twisted Lay length ≤38 ≤38 ≤38 ≤38 Pair Diameter 2.802.80 2.80 Cable Core Composing 4 twisted pairs 4 twisted pairs 4 twistedpairs 4 twisted pairs stranded together stranded together strandedtogether stranded together Lay length ≤120 ≤120 ≤120 ≤127 Diameter 5.2 ±0.5 5.2 ± 0.5 5.2 ± 0.5 Sheath Material FR-PVC CM-LSZH FR-PVC FEP Ripcord Present under the Present under the Present under Present undersheath sheath the sheath the sheath Wall thickness 0.50 0.50 0.50 0.33Diameter 6.6 ± 0.5 6.6 ± 0.5 6.6 ± 0.5 6.3 Electrical Conductor ≤9.38Ω/100 m ≤9.38 Ω/100 m ≤9.38 Ω/100 m 10.3 Ω/Mft ± 10% Performanceresistance at 20° C. Insulation resistance ≤5000 MΩKm(DC ≤5000 MΩKm(DC5000 MΩKm(DC 500 V Charged 1 Min) 500 V Charged 1 Min) 500 V Charged 1Min) Voltage endurance DC 1500 V/min DC 1500 V/min DC 1500 V/min Mutualcapacitance ≤7.0 nF/100 m ≤7.0 nF/100 m ≤7.0 nF/100 m 15.0 pF/ft ± 10%Core-core ≤5% ≤5% ≤5% resistance unbalance

The connector used with the cable of the present disclosure has anenlarged inner diameter of the RJ-45 front side to allow 20 AWGconductors to slide underneath the gold contact prongs. The gold prongsneed to accommodate the 20 AWG size and the rear side has a metal clampto hold the jacket (7.0 mm OD). The outside dimensions of the RJ-45 plugand boot are identical to the size of a regular RJ-45 patch cord,therefore the patch cord can plug into the regular patch panel and/orother connected devices, such as a security camera. Further details ofthe connector are shown and described below.

Tests on the new 20 AWG cable connected to a video camera showed thatthe cable worked up to 960 feet with a 1920×1080 high-resolutionpicture, whereas conventional Cat 6 cable worked only to 650 feet andthe conventional Cat 5e worked to only 600 feet. This is over a 45%improvement in reach and the cable met all TIA electrical requirementsfor Cat 5e performance to 100 MHz and extrapolated to 350 MHz.

With 960 feet of usable length the present cable can extend 292 meters,which is almost three times the 100 meter distance for conventioncategory cables. It is also possible that the FEP and polyethyleneversions may be a little better in reach due to the differentdissipation factor between FEP and PE insulation.

Some comments are noted here. First, this cable has an advantage sincein addition to carrying video and power it also complies with TIAelectrical performance requirements for Cat 5e. Second, it is possibleto include a spline separator which will minimize cross-talk. Third,CCTV is a good application for the type of cable of the presentinvention, since the reach is almost tripled. Fourth, when TIA standardswere written 100 meters was chosen as the test length of a typicalinstallation, but allowed 300 meters for indoor multi-mode opticalfiber. Fifth, security cameras are just one possible application of thepresent disclosure. Data centers, airport concourse signage and othervery large commercial and government installations are examples of otherapplications which would benefit. There may also be a use for this cablein solar and wind power and control cables, so that one cable couldsupport a typical installation, rather than requiring a bundle ofcables. The cable may also extend VOIP distances and network distancesby the same lengths as CCTV without the need for IDF equipment orclosets.

FIGS. 3-7 illustrate an RJ-45 style connector 36 used with the cable ofthe present disclosure. It has a two-part shell including a housing 38and a shield 40. The housing is made of a suitable plastic material,such as polycarbonate. The housing is a generally five-sided enclosurehaving a top wall 42, side walls 44, a bottom wall 46 and a front endwall 48. There is no end wall at the rear edges 50 of the side walls 44,thereby leaving the housing open for receiving an insert as describedbelow. The side walls 44 are joined near their rear edges 50 by atransverse lip 52 that extends downwardly from the bottom wall 46.

The lip 52 leads into the interior of the housing which includes anangled ramp 54 extending upwardly from the bottom wall 46. At the top ofthe ramp are four semi-cylindrical conductor supports 56, as best seenin FIG. 4. The supports 56 are offset from a facing set of foursemi-cylindical conductor guides 58 which extend downwardly from the topwall 42. The supports 56 and guides 58 define a diameter sufficient toreceive 20 AWG wires. A diameter of about 1.50 mm has been foundsufficient. The supports 56 and guides 58 are staggered or offset fromone another to provide sufficient space for the large diameter wiresused herein.

The centers of the supports and guides are each aligned with one ofeight compartments which are defined by a set of seven partitions 60.The partitions are vertical plates located forwardly of the ramp 54 andinside the confines of the side walls 44 and front end wall 48. Thefront end of the housing has a window or opening at the front lowercorner where the front end wall 48 meets the bottom wall 46. Thepartitions 60 extend into the window space to create eight compartmentsthat each receive a contact blade 62.

Details of one of the contact blades 62 are seen in FIG. 8. The bladesmay be made of copper alloy plated with a 50 μ-inch layer of gold over a100 μ-inch underplate of nickel in the contact area. The contact blade62 is an insulation displacement type blade that has a body 64 whichdefines a rail 66. A plurality of prongs 68 extend upwardly from thebody 64. Four of the blades have prongs of extra length to reach theupper row of wires. With the blades 62 installed in the compartments ofthe connector housing the rails 66 are exposed at the window where theyare engageable with a crimping tool during installation of the connectoron a cable. After insertion of the wires and their associated insertinto the housing, the wires are located in the spaces of the supports 56and guides 58 and above the prongs of the blades 62. Then the blades arecrimped such that the prongs 68 are forced upwardly into and through theinsulation of the wires and into engagement with the conductors of thewires.

Exterior features of the connector 36 include a block 70 formed at thecorner where the top wall 42 meets the front end wall 48. A latch 72 iscantilevered from the block 70. The latch 72 is flexible and engageablein the usual manner with an RJ-45 receptacle to releasably retain theconnector 36 in the receptacle. A release lever 74 attached to andextending from the latch can be depressed to allow the latch to escapethe receptacle and permit withdrawal of the connector therefrom.

The side walls 44 at their front ends have protrusions 76 (FIGS. 3 and4) of slightly increased thickness compared to the remainder of the sidewall. A rectangular hiatus in this increased thickness portion defines adepression 78 in the outer surface of the side wall, as best seen inFIG. 4. The depression receives an extension of the shield 40 as will beexplained below.

Details of the shield 40 will now be described. The shield is preferablymade of metal, such as a copper alloy. It is a stamped or otherwiseformed sheet that is folded into a four-sided enclosure having a roof 80joined to a pair of side panels 82 which in turn have a pair of bottomflaps 84. The bottom flaps are connected to one another at a dovetailjoint 86 (FIG. 7). The side panels include a rectangular extension 88 atthe forward end. The extension 88 fits in the depression 78 formed inthe outer surface of the side walls 44 of the housing. The thickness ofthe side panel is the same as the thickness of the protrusions 76. Thus,the outer surfaces of the side walls 44 and side panels 82 are coplanarwith one another and present a smooth interface at their junctionpoints.

The roof 80 of the shield 40 has two three-sided piercings that form apair of tabs 90. The tabs are bent inwardly slightly to engagedepressions in the top wall 42 of the housing and thereby retain theshield on the housing. The rear edge of the roof 80 carries a clamp 92which includes a strap 94 and a stirrup 96. The clamp starts outupraised as shown in FIG. 3. After insertion of the wires the strap 94gets folded down so the stirrup is placed around the insulation of thewires and then the stirrup 96 is crimped to fasten the wires to thehousing and provide strain relief.

FIGS. 9-12 illustrate an insert 98 that is used to constrain the wiresin the desired configuration prior to placing the insert in the housing38. The insert has a block 100 through which two staggered rows or fourholes 102 are formed. These holes are arrayed similarly to the supports56 and guides 58 so they align therewith upon placement of the insert inthe housing. The diameters defined by the holes are the same as for thesupports and guides, namely 1.50 mm. It will be noted in FIG. 12 thatthe block 100 is tapered from height of 3.20 mm the front end to 3.40 mmat the back end. This assists with installation of the insert into thehousing 38 of the connector 36.

In an alternate embodiment four twisted pairs of 22 AWG wires could beused. These wires are easier to bend and can be used with standard RF-45connectors. The individual and very tight lay lengths are indicatedshown below. The left-hand rotation is normally as shown, which is blue,orange, green and brown. The four twisted pairs are then twistedtogether in the bundle twist lay noted below, which is also a left-handlay. Both the individual pairs and the four-pair bundle are twisted inthe same left-hand direction and this slightly tightens the twist of theindividual pairs. Both operations need to be performed very accurately.The pair lay length could be less than or equal to about 1.496″. Thecable lay length could be less than or equal to about 4.724″. Morespecifically, the lay length of each pair is Blue: 0.5460″; Orange:0.8996″; Green: 0.6929″; Brown: 0.8047″. Further, the four pairs cablinglay length is 3.9370″.

The compatible twist lays indicated result in electrical performancethat is vastly superior to that of a Cat 5e cable. Minimizing thecross-talk (high frequency noise) allows the digital signals in thecable to travel two to three times the distance of a Cat 5e cable, whichis restricted to 100 meters (328 ft). The unique twist-lay combinationtogether with the 22 AWG conductors minimizes the DC resistance of thecable significantly. Thus, the signal travels a longer distance and isless susceptible to noise. Since this cable meets and vastly exceeds theelectrical performance specified for Cat 5e cables by TIA, which is avery good reference point, the cable of the present disclosure is anespecially suitable cable for digital video surveillance and otherdemanding applications which require longer cable lengths than thosespecified by TIA.

The following chart shows test results of the 20 AWG and 22 AWG cablesof the present disclosure compared to 23 AWG and 24 AWG cables of theprior art. These tests were performed using an Intellinet 560542 ManagedSwitch together with three different brands of IP video cameras. Notethe 20 AWG and 22 AWG cables of the present disclosure provide usablecable length increases ranging from at least 26% (for 22 AWG on the ACTiand Bosch cameras compared to 23 AWG) to 60% (for 20 AWG on the Axiscamera compared to 24 AWG).

Cable Size Camera Resolution Frames/Sec. Link Setting Cable Length Feet20 AWG AXIS Q6045 PTZ 1920 × 1080P 30 LAPTOP MP OPTIMIZED 960 BOSCH IP5000 1440 × 1080P 12 LAPTOP 1 MP OPTIMIZED 900 5 MP BOX H264 ACTi D22FA5 MP * 1920 × 1080P 5 ACTi ENR- Auto 800 1000 DVR 22 AWG AXIS Q6045 PTZ1920 × 1080P 30 LAPTOP MP OPTIMIZED 875 BOSCH IP 5000 1440 × 1080P 12LAPTOP 1 MP OPTIMIZED 825 5 MP BOX H264 ACTi D22FA 5 MP 1920 × 1080P 5ACTi ENR- Auto 825 1000 DVR 23 AWG AXIS Q6045 PTZ 1920 × 1080P 30 LAPTOPMP OPTIMIZED 650 (Cat 6) 24 AWG AXIS Q6045 PTZ 1920 × 1080P 30 LAPTOP MPOPTIMIZED 600 (Cat 5e) * All using Intellinet 560542 Managed Switch setto 10 MP Managed except * is set to auto

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modification can be madewithout departing from the spirit and scope of the invention disclosedherein. For example, in addition to the jacket 12, ripcord 14 andtwisted pairs 18-24, an alternate embodiment may include an optionalseparator, a shield layer, a tape layer and/or a drain wire, the latterof which would be located between the shield and tape layers. The shieldlayer may be made of aluminum foil and the tape layer may be polyesterfilm, such as Mylar®.

The invention claimed is:
 1. A power-over-ethernet cable, comprising:four twisted pairs of wires and no other wires, each wire having a 20AWG conductor or each wire having a 22 AWG conductor; and a connector,wherein the cable has a length greater than 100 meters, and the wiresare configured for transmission of both power and data.
 2. Thepower-over-ethernet cable of claim 1, wherein the connector isconfigured for receipt by an RJ-45 style jack.
 3. Thepower-over-ethernet cable of claim 2, wherein each wire has a 20 AWGconductor, the connector includes an insert defining a plurality ofholes, and each wire is received by a different one of said holes. 4.The power-over-ethernet cable of claim 2, wherein each wire has a 22 AWGconductor, and the connector comprises an RJ-45 style plug.
 5. Thepower-over-ethernet cable of claim 1, further comprising a layer ofinsulation around each conductor, wherein the insulation is comprised ofa material selected from the group of fluorinated ethylene propylene,polypropylene, or high density polyethylene.
 6. The power-over-ethernetcable of claim 1, configured for association to a power supply at onlyone of its ends.
 7. The power-over-ethernet cable of claim 1, having alength of at least 292 meters.
 8. The power-over-ethernet cable of claim1, further comprising a spline separator.
 9. An electrical powerdelivery system, comprising: a jack; and a power-over-ethernet cableincluding four twisted pairs of wires and no other wires, each wirehaving a 20 AWG conductor or each wire having a 22 AWG conductor; and aconnector received by the jack, wherein the cable has a length greaterthan 100 meters, and the wires are configured for transmission of bothpower and data.
 10. The electrical power delivery system of claim 9,wherein the jack comprises an RJ-45 style jack.
 11. The electrical powerdelivery system of claim 10, wherein each wire has a 20 AWG conductor,the connector includes an insert defining a plurality of holes, and eachwire is received by a different one of said holes.
 12. The electricalpower delivery system of claim 10, wherein each wire has a 22 AWGconductor, and the connector comprises an RJ-45 style connector.
 13. Theelectrical power delivery system of claim 9, further comprising a layerof insulation around each conductor, wherein the insulation is comprisedof a material selected from the group of fluorinated ethylene propylene,polypropylene, or high density polyethylene.
 14. The electrical powerdelivery system of claim 9, wherein the cable is not connected to apower-over-ethernet injector.
 15. The electrical power delivery systemof claim 9, wherein the cable is not connected to a mid-span powersupply.
 16. The electrical power delivery system of claim 9, furtherincluding only a single power supply, wherein the power supply isassociated with one end of the cable.
 17. The electrical power deliverysystem of claim 9, wherein the cable has a length of at least 292meters.
 18. The electrical power delivery system of claim 9, wherein thecable includes a spline separator.
 19. The electrical power deliverysystem of claim 9, wherein the cable is not connected to a booster. 20.The electrical power delivery system of claim 9, wherein the cable isnot connected to an intermediate distribution frame.
 21. Apower-over-ethernet cable, comprising: four twisted pairs of wires andno other wires, each wire having a 20 AWG conductor or each wire havinga 22 AWG conductor; and a connector, wherein the cable has a lengthgreater than 100 meters and complies with Ethernet data transmissionprotocol and is used for power-over-ethernet transmission protocols. 22.An electrical power delivery system, comprising: a jack; and apower-over-ethernet cable including four twisted pairs of wires and noother wires, each wire having a 20 AWG conductor or each wire having a22 AWG conductor; and a connector received by the jack, wherein thecable has a length greater than 100 meters and complies with Ethernetdata transmission protocol and is used for power-over-ethernettransmission protocols.